1. Technical Field
The present invention relates to an apparatus for converting converted data that belongs to an m-axis (where, m is an integer that is equal to or larger than 2) data space and a method thereof.
2. Related Art
In the case of displaying a still image or an image on a display screen of a light modulation device such as a liquid crystal display panel, image data that forms such an image is generally converted into data that is suitable to be output to pixels that constitute a display screen to be output. In a printing technology field, not limited to the image display, RGB image data is converted into ink colors that can be processed in a printer. In such a data conversion, a lookup table is commonly used to mediate simplicity in the conversion process (for example, see JP-A-2001-36755).
JP-A-2001-36755 discloses the use of a 3-dimensional lookup table (hereinafter referred to as a “3D-LUT”) in which respective RGB axes have the same number n of lattice points in order to convert data in a color space that is represented by three data axes of RGB into data in another color space. According to this 3D-LUT, a 3D square lattice is provided with n3 lattice points, and correction data for data conversion at respective lattice points are stored in eight memories that corresponds to the number 23 of lattice points of the square lattice. In storing the correction data, correction data of the respective lattice points are sequentially stored in the eight memories in combination of even and odd numbers of three-axis coordinate numbers in observing the combination of the even and odd numbers of the coordinate numbers of the three axes of RGB in the case where the lattice points of the respective axes are inscribed by positive integers starting from zero in the range of 0 to n−1 on the three-axis coordinates of RGB. Also, eight lattice points that surround a conversion target point having data that is the subject of data conversion are obtained, and data (RGB data) on the conversion target point is data-converted through reception of the correction data that the respective lattice points have in a complementary computation technique.
The data conversion technique using the 3D-LUT may also be applied to a case where a still image or a video is displayed on the display screen such as a liquid crystal display panel or the like based on the image data in addition to the above-described color conversion. That is, if it is assumed that the length and breadth of an image that is displayed on a liquid crystal display panel or the like are represented by x and y-axes and a gray scale when gray scale expression is performed for each pixel is represented by a z-axis, the image data that corresponds to each pixel becomes data indicated on three data axes, and thus the correction of the image data that corresponds to the pixel can be performed by a data conversion technique using the 3D-LUT. However, since there is a restriction in that the respective axes of the 3D-LUT have the same number of lattice points and the correction data at the respective lattice points is stored in eight memories that correspond to the number of lattice points of the square lattice, there is a need for improvement of its genericity as described below.
In the case of performing a high-resolution image display in the liquid crystal display panel, the aspect ratio of the liquid crystal display panel is sometimes different, and thus the length of the x-axis is different from the length of the y-axis in the display area of an image. Because of this, the number of lattice points on the x-axis may be different from the number of lattice points on the y-axis. However, according to the above-described technique, due to the limitation in that the respective x, y, and z-axes have the same number of lattice points, an address operation for storing data that is different from that in the above-described technique is required and thus its improvement is required.